A general box making machine is for making a box body (a corrugated box) by processing a sheet material (for example, a corrugated sheet) and is composed of a feeding unit, a printing unit, a die cut unit, and the like. Here, the die cut unit is for forming a creasing line which becomes a fold line or processing a groove which forms a flap, a glue tab for joining, or a hole for a hand hole, with respect to a printed corrugated sheet.
Such a die cut unit has an anvil cylinder and a knife cylinder which are disposed one above the other. The anvil cylinder and the knife cylinder are horizontally disposed, are rotatably supported on a frame at both end portions, and can be rotated in the opposite directions to each other by a drive unit. A knife mounting base is mounted on the outer peripheral surface of the knife cylinder, and a punching is mounted on the knife mounting base. For this reason, when the corrugated sheet is transported between the anvil cylinder and the knife cylinder, for example, hole cutting is performed on the corrugated sheet by the punching knife.
As such a die cut unit (a rotary die cutter), there is, for example, a die cut unit disclosed in PTL 1 below. In PTL 1, a fixing hole which is opened in an outer peripheral surface, an acting force generator disposed in the fixing hole, a sliding parts capable of selectively generating a suction force or a repulsive force with respect to the acting force generator, and a locking member which is configured integrally with the sliding parts and protrudes outward from the outer peripheral surface of a knife cylinder when a repulsive force is generated between the sliding parts and the acting force generator are provided, and a peripheral wall portion of a through-hole perforated in a knife mounting base is fitted between the outer peripheral surface of the knife cylinder and the locking member, whereby the knife mounting base is fixed to the outer peripheral surface of the knife cylinder.